Effect of physical and chemical treatments on breaking seed dormancy of datura (Datura stramonium L.)

Datura is one of the most important medicinal plants that for production of various alkaloids. Seed dormancy and the problem of germination are the most important barrier to produce this plant. In order to solve the germination problem in this important medicinal plant, the present study was carried out as a factorial experiment with three factors based on completely randomized design with three replications. The first factor consisted of two datura ecotypes (Hamadan and Esfahan), the second factor included three levels of physical treatments of breaking dormancy (no scratching, scratch with sandpaper and wet bathing of bain marie bath for 7 days at a temperature of 60 ° C, scratch with sandpaper and dry chilling for 7 days at 4 ° C) and the third factor included five levels of chemical treatments of breaking dormancy (no application of chemical treatments, NaOH 20%, NaOH 20% and gibberellin 500 ppm, NaOH 20% and potassium nitrate 300 ppm, NaOH 20% and gibberellin 500 ppm and potassium nitrate 300 ppm). Interaction of ecotypes and seed dormancy breaking treatments was significant for most traits except for number of leaves per plant, root fresh weight, shoot length and stem fresh weight. The results showed that the chemical treatment of NaOH 20% and gibberellin 500 ppm, was the best dormancy braking treatment for the fresh harvested seeds. Therefore, using this treatment without significant damage to the seeds, to break seed dormancy about 80 percent is recommended.